docs(agent): file #142 — a rebuild while docked performs an undock

Bernardo: every rebuild while docked re-lights the panel and throws a
workspace onto it; he re-picks Dock mode by hand. Static diagnosis, three
steps, each already proven by our own code:

- dock mode is runtime-only (`keyword monitor <internal>, disable`,
  hyprland.nix:205) and absent from state.json — the one display setting
  outside the in-flake state;
- the config's only monitor line is the catch-all `,preferred,auto,1`, so
  a reload re-enables every output. The undock path already uses `hyprctl
  reload` AS the hammer that re-enables a disabled panel (hardware-proven
  2026-07-14) — so a rebuild performs an undock by construction;
- reconcile diffs `monitors all`, which lists disabled monitors, so the
  set is unchanged across the flip and the watcher never sees it. Blind
  spot of round 4/5's "the output set is the truth".

Notes the trap: baking the disable into the config is a zero-output
session at login (the #100/#127 brick). Persist intent, re-assert from
the watcher, gate on an external being present.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

agent/BACKLOG.md

@@ -271,6 +271,53 @@ bug, not the instance: nothing today asserts that a whole-swap's on-click
 survives Waybar's actual environment, so the next hand-written jsonc can
 reintroduce it silently.
 
+### 142. A rebuild while docked undoes dock mode (the panel comes back, a workspace jumps to it)
+
+Bernardo 2026-07-16: every rebuild while docked lands in the undocked state —
+laptop panel back on, a workspace moved onto it — and he re-picks **Dock mode**
+in the Display menu by hand. Diagnosed statically on the dev box (no session
+disruption needed; our own code already proves each step):
+
+1. **Dock mode is runtime-only.** `nomarchy-display-transition dock` ends with
+   `hyprctl keyword monitor <internal>, disable` (`hyprland.nix:205`) — a live
+   compositor command. Nothing writes it down: his `state.json` has no display
+   key at all, so dock mode is the one display setting outside the in-flake
+   state, which is exactly why it cannot survive anything.
+2. **Any config reload re-enables everything.** The generated config's only
+   monitor line is the catch-all `monitor=,preferred,auto,1` (live
+   hyprland.conf:175 — he has no `displayProfiles`), so a reload turns every
+   output back on, `eDP-1` included, and Hyprland puts a workspace on the
+   output that just appeared. We do not have to guess that a reload does this:
+   the **undock** path uses `hyprctl reload` deliberately, as the hammer that
+   re-enables an inert disabled panel, hardware-proven 2026-07-14
+   (`hyprland.nix:225`). A rebuild reloads the config and therefore *performs
+   an undock*, precisely and by construction.
+3. **The watcher cannot see it happen.** `reconcile` diffs `outputs()` =
+   `hyprctl monitors all` (`:505`), which lists **disabled** monitors too. So
+   the connected set is byte-identical before and after the flip, `cur !=
+   known_outputs` is false, and reconcile returns having done nothing. The
+   watcher tracks connect/disconnect and is structurally blind to
+   enable/disable — the blind spot in round 4/5's "the output set, not the
+   event, is the truth" (ROADMAP § Docking rounds 4–5).
+
+**Shape, and the trap in the obvious fix.** The tempting move is to bake the
+disable into the config (state → `monitor=eDP-1,disable`) so a reload preserves
+it. **Do not** without a guard: a persisted disable with no external attached
+is a zero-output session at login — the black brick #100 and #127 are both
+about. The config is evaluated with no knowledge of what is plugged in, so it
+must keep defaulting to "everything on". Better: persist the *intent*
+(`settings.display.dockMode`, in-flake, menu-writable — the philosophy this
+currently violates) and let the **watcher** re-assert it, since only it knows
+what is live. That needs reconcile to also track the *enabled* set, so
+"internal came back on while an external is present and the state says docked"
+becomes an event it can act on — which fixes the reload case and any other
+path that silently re-enables the panel. Gate re-assertion on an external
+actually being present, never on the state key alone.
+
+Pass = docked, `nomarchy-home` (and `nomarchy-rebuild`) → panel stays off, no
+workspace moves, no menu trip; undocked rebuild unchanged; unplug while the
+state says docked still restores the panel.
+
 ### 120. A netinstall ISO, next to the fat offline one
 
 Bernardo 2026-07-14, after seeing the measured size: **keep the current ISO